<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>盒子模型详解</title>
	<style type="text/css">
		*{
			margin: 0px;
			padding: 0px;
		}
		.box{
			 width:300px;
			 height: 300px;
			 background: gray; 
			 margin: 10px;
			 padding: 10px;
			 border: 5px solid red;
			 display: inline-block;
		}
		.box1{
			margin: 20px;
			padding: 20px;
		}
		.box2{
			margin: 20px;
			padding: 20px;
		}
		.box3{
			width: 200px;
			height: 200px;
			background: red;
			padding: 20px;
		}


	</style>
</head>
<body>
 		<div class="box box1">这是一个盒子<div class="box3">这是盒子里面的盒子</div></div>
 		<div class="box box2">这也是一个盒子</div>
	
</body>
</html>